Potentiometer

ABSTRACT

A potentiometer comprising a slider and a resistance presenting a conductive track, as well as an intermediary member having the shape of a resiliently deformable sheet interposed between the slider and the conductive track, at least a portion of this sheet, situated opposite the track, being conductive, wherein the sheet rests on a cushion made of flexible and compressible material which maintains it at a distance from the conductive track and which is elastically deformed under the effect of the pressure exerted on the sheet by the slider, so that the portion of the sheet adjacent the slider comes in contact with the track.

United States Patent 1191 Meylan-Rochat Nov. 13, 1973 POTENTIOMETER3,516,041 6/1970 Estlick 338/154 [75] Inventor: Andre Meylan-Rochat, LeBrassus,

S i l Primary ExaminerBernard A. Gilheany Assistant Examiner-D. A. Tone[73] Assigneez Parechoc S.A., Vaud, Switzerland Atmmey Kenwood Ross eta1 [22] Filed: Sept. 19, 1972 [21] Appl. No.: 290,348 ABSTRACT- Apotentiometer comprising a slider and a resistance [30] F i Applicationpriority Data presenting a conductive track, as well as an intermedisept20 1971 Switzerland 13740! ary member having the shape of a resilientlydeform- May 9 972 Germany 23 59 able sheet interposed between the sliderand the conductive track, at least a portion of this sheet, situated 52US. Cl. 338/154 I PSite the being cmductive wherein 511 1m. 01 1101c5/00 sheet cushim made flexible and 58 F ld is h 154 Pressible materialwhich maimains it a d'stance I l o are 338/ from the conductive trackand which is elastically deformed under the effect of the ressureexerted on the [56] References Cited p sheet by the slider, so that theportion of the sheet ad- UNITED STATES PATENTS jacent the slider comesin contact with the track. 3,070,768 l2/l962 Mairs 338/154 3,377,6044/1968 Forrest 338/154 7 Claims, 3 Drawings PAIENIEnnuv 13 I9753.772.629

FIG. 7

FIG. 2

POTENTIOMETER The present invention relates to a potentiometercomprising a slider and a resistance provided with a conductive track aswell as an intermediary member having the shape of a resilientlydeformable sheet, interposed between the said slider and the saidconductive track, at least a portion of this sheet, situated oppositethe said track, being also conductive.

This potentiometer is characterized by the fact that on the shaft,provided with an extension 19a having the the said sheet rests on acushion made of flexible and compressible material which maintains it atdistance from the conductive track and which is elastically deformedunder the effect of the pressure exerted on the said sheet by theslider, so that the portion of the sheet adjacent to the slider comes incontact with the said track.

The drawing shows, by way of example, two embodiments of the object ofthe invention and one modification. I

FIGS. 1 and 2 are axial sectional views of two different embodiments ofa potentiometer, and

FIG. 3 is an axial sectional view of a detail of a modification.

The potentiometer represented in FIG. 1 comprises a cylindrical casing,made of plastic material, constituted by a main body 1 in which isengaged a cover 2. The booy carries an annular coiled resistance 3 withwhich cooperates, indirectly, a rotative slider constituted by a radialarm 4 supported by a shaft 5 rotatably mounted, by means of a rollingbearing 6, on the cover 2. The shaft of this slider is coaxial to theresistance 3.

The arm 4 of the slider carries, at its free extremity, a rotativeroller 7 bearing on a metallic disc 8 coaxial to the shaft 5, having theshape of a thin elastic sheet, supported by a cushion 9 made of flexibleand compressible material, for instance rubber, also coaxial to theshaft 5, located inner the resistance 3. The sheet 8 extends beyond thecushion 9 and extends, by its periphery, above the resistance 3, whilethe roller 7 bears on this sheet within the resistance with respect tothe center of the apparatus, in the vicinity of the periphery of thecushion 9.

Owing to the presence of the cushion 9, whichreturns resiliently thesheet 8 into its rest position, in

which it is plane and situated at a slight distance from the resistance3, the sheet can be choosen very thin, that permits, opposite the placewhere is the roller 7, to incurve itself while taking the shape of theroller, and thus to come in contact with the resistance substantially ona point, that increases the degree of resolution of the potentiometer,which is expressed by the value of the minimum displacement of theslider able to produce a sensible variation of the resistance.

The connecting electric threads of the potentiometer, which are notrepresented, enter into the casing 1-2 through a sleeve 10 and areconnected, two at the resistance 3 and a third one to the circular sheet8.

The embodiment of FIG. 2 distinguishes from the first one principally bythe fact that the shaft, designated by 11, operating the arm 12 of theslider, is extended under this arm and enters into the body 13 of thecasing in which it is supported by a rolling bearing 14. It is moreoversupported by the cover 15 of the casing through the intermediary of arolling bearing 16, as in the first embodiment.

shape of a segment extending on while its rear extremity, which ishollow at 20, is rigid with a sleeve 21, also mounted on the shaft,provided with'an extension 21a, having the shape of a segment extendingon 180.

This arrangement permits to mount several potentiometers as a set, thefront extremity of the shaft 11 of each of them, excepted the endpotentiometer of the set, being engaged in the recess 20 of the adjacentpotentiometer. The mutual engagement of the extensions 19a and 21a hasfor effect that the shaft of each potentiometer is rigid with the shaftof the adjacent potentiometer.

The present potentiometer can serve either for varying the value of aresistance, i.e. the resistance 3, or for operating as a measuringinstrument of the angular position of a rotative movable element, theinformation being given by the instantaneous value of the resistance. Inthis last case, especially, a high degree of resolution of thepotentiometer is desired.

The invention is not limited to the potentiometers as disclosed andrepresented but can be applied, for instance, to potentiometers in whichthe resistance, which is not coiled, can be constituted by a mere trackof carbon, or by a conductive plastic material. The intermediary sheet,interposed between the conductive track of the resistance and the slidercan be not plane, but, may be, conical, or cylindrical, provided it isable to be elastically deformed.

The potentiometer can also not be of the type with an annular resistanceand with rotative slider, but also of the type with a rectilinearresistance and with a slider which is movable in a translation motion.In this case, for instance, the metallic blade can protrude on bothsides of the resistance and be supported, under its protruding portions,by two elastic cushions, parallel to each other, or by one elasticcushion in which the resistancewill be embedded.

In the examples represented, the resistance is circular, so that itsvalue varies linearly, proportionally to the rotation of the slider. Asa modification, the shape of the resistance can be different, and havefor instance the shape of a spiral, so as to give an information whichis not directly proportional to the rotation of the slider.

What I claim is:

1. Potentiometer comprising a slider and a resistance presenting aconductive track, as well as an intermediary member having the shape ofa resiliently deformable sheet, interposed between the said slider andthe said conductive track, at least a portion of this sheet, situatedopposite the said track, being also conductive, characterized by thefact that the said sheet rests on a cushion made of a flexible andcompressible material and which maintains it at distance from theconductive track and which is elastically deformed under the effect ofthe pressure exerted on the sheet by the slider, so that the portion ofthe sheet adjacent to the slider comes in contact with the said track.

2. Potentiometer' as claimed in claim 1, the slider of which is rotativeand the resistance of which is annular and coaxial to the center ofrotation of the slider, characterized by the fact that the said cushionis circular and is located inner the said resistance, the intermedi arysheet, also circular, being coaxial to the said cushion and protrudingbeyond the cushion so as to extend, by its periphery, above the saidresistance.

Potentiometer otentiometer as claimed in claim 2, characterized by thefact that the slider comprises a radial arm at the free extremity ofwhich is rotatably mounted a roller bearing on the said sheet.

4. Potentiometer as claimed in claim 2, characterized by the fact thatit comprises a cylindrical casing including its different elements, oneof the axial walls of which is traversed by a shaft rigid with theslider, and which serves to operate the slider, this shaft beingrotatably mounted in the said wall.

5. Potentiometer as claimed in claim 4, characterized by the fact thatthe said shaft traverses the said casing and is also rotatably mountedin the second axial wall thereof.

6. Potentiometer as claimed in claim 5, characterized by the fact thatone of the extremities of the said shaft is provided with coupling meansthe shape of which is shape of the resistance is not circular.

1. Potentiometer comprising a slider and a resistance presenting aconductive track, as well as an intermediary member having the shape ofa resiliently deformable sheet, interposed between the said slider andthe said conductive track, at least a portion of this sheet, situatedopposite the said track, being also conductive, characterized by thefact that the said sheet rests on a cushion made of a flexible andcompressible material and which maintains it at distance from theconductive track and which is elastically deformed under the effect ofthe pressure exerted on the sheet by the slider, so that the portion ofthe sheet adjacent to the slider comes in contact with the said track.2. Potentiometer as claimed in claim 1, the slider of which is rotativeand the resistance of which is annular and coaxial to the center ofrotation of the slider, characterized by the fact that the said cushionis circular and is located inner the said resistance, the intErmediarysheet, also circular, being coaxial to the said cushion and protrudingbeyond the cushion so as to extend, by its periphery, above the saidresistance.
 3. Potentiometer otentiometer as claimed in claim 2,characterized by the fact that the slider comprises a radial arm at thefree extremity of which is rotatably mounted a roller bearing on thesaid sheet.
 4. Potentiometer as claimed in claim 2, characterized by thefact that it comprises a cylindrical casing including its differentelements, one of the axial walls of which is traversed by a shaft rigidwith the slider, and which serves to operate the slider, this shaftbeing rotatably mounted in the said wall.
 5. Potentiometer as claimed inclaim 4, characterized by the fact that the said shaft traverses thesaid casing and is also rotatably mounted in the second axial wallthereof.
 6. Potentiometer as claimed in claim 5, characterized by thefact that one of the extremities of the said shaft is provided withcoupling means the shape of which is complementary of the shape thecoupling means provided at its other extremity, the whole in such a wayas to permit to mount several potentiometers in a set, the couplingmeans of each potentiometer of the set being meshing with thecomplementary coupling means of the adjacent potentiometer, so that theshafts of all the potentiometers of the set be rigid with each other. 7.Potentiometer as claimed in claim 1, the slider of which is rotatable,characterized by the fact that the shape of the resistance is notcircular.